Sprain, strain, pulled muscle?

Hot or cold?
As soon as possible after an injury: wrap ice cubes in a cloth and massage the injured area for five to 10 minutes every couple of hours until heat and swelling are gone.

If you keep ice on too long, it swells blood vessels -- just the opposite of what you want at this point.

Or you can use gel cold packs, which are okay to leave on longer (until they're no longer cold).

Elevate the injured area as much as possible.

Compress the injury with an elastic wrap to help keep swelling down. Make sure the compression is snug, but not too tight -- which could cause damage.

Apply heat when the injury is no longer red and swollen (usually after a couple of days). Heat helps speed healing by increasing blood flow.

If pain and swelling don't begin to subside after several days, see a doctor.

Source: American Running Association